Effects of medical therapy on insulin resistance and the cardiovascular system in polycystic ovary syndrome

Diabetes Care. 2007 Mar;30(3):471-8. doi: 10.2337/dc06-0618.


Objective: We aimed to determine the impact of medical therapy for symptom management on insulin resistance, metabolic profiles, and surrogate markers of cardiovascular disease in polycystic ovary syndrome (PCOS), an insulin-resistant pre-diabetes condition.

Research design and methods: One hundred overweight women (BMI >27 kg/m2), average age 31 years, who were nonsmokers, were not pregnant, did not have diabetes, and were off relevant medications for 3 months completed this 6-month open-label controlled trial. Randomization was to a control group (higher-dose oral contraceptive [OCP] 35 microg ethinyl estradiol [EE]/2 mg cyproterone acetate, metformin [1 g b.d.] or low-dose OCP [20 microg EE/100 microg levonorgestrel + aldactone 50 mg b.d.]). Primary outcome measures were insulin resistance (area under curve on oral glucose tolerance test) and surrogate markers of cardiovascular disease including arterial stiffness (pulse wave velocity [PWV]) and endothelial function.

Results: All treatments similarly and significantly improved symptoms including hirsutism and menstrual cycle length. Insulin resistance was improved by metformin and worsened by the high-dose OCP. Arterial stiffness worsened in the higher-dose OCP group (PWV 7.46 vs. 8.03 m/s, P < 0.05), related primarily to the increased insulin resistance.

Conclusions: In overweight women with PCOS, metformin and low- and high-dose OCP preparations have similar efficacy but differential effects on insulin resistance and arterial function. These findings suggest that a low-dose OCP preparation may be preferable if contraception is needed and that metformin should be considered for symptomatic management, particularly in women with additional metabolic and cardiovascular risk factors.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Area Under Curve
  • Body Mass Index
  • Cardiovascular Physiological Phenomena*
  • Contraceptives, Oral / therapeutic use*
  • Female
  • Femoral Artery / physiopathology
  • Glucose Tolerance Test
  • Homeostasis
  • Humans
  • Insulin / blood
  • Insulin Resistance / physiology*
  • Metformin / therapeutic use*
  • Models, Biological
  • Overweight
  • Polycystic Ovary Syndrome / blood
  • Polycystic Ovary Syndrome / drug therapy*
  • Polycystic Ovary Syndrome / physiopathology*


  • Contraceptives, Oral
  • Insulin
  • Metformin

Associated data

  • ISRCTN/ISRCTN51367236